The present invention relates to the art of hinges and more particularly to an adjustable cam operated hinge.
The invention is particularly applicable to cam operated hinges for use with doors for lavatory, shower, dressing, or other small compartments and will be described with particular reference thereto; however it will be appreciated that the invention has broader applications and may be used in numerous other hinge applications.
Cam operated hinges, especially adjustable hinges, are adaptable to a wide variety of applications. They are suitable wherever it may be desirable to have a door biased to a neutral position. Such hinges are particularly well suited for use with doors for lavatory, shower, dressing, or other analogous small compartments. In these applications, the hinge is generally subjected to constant use. Such hinges must be functionally reliable, extremely durable, self-contained, and easily adjusted when in a mounted position. The hinge must also be attractive, with an aesthetically pleasing appearance.
Heretofore, adjustable cam operated hinges were generally comprised of a large number of machined or molded pieces. These pieces were primarily of plastic construction because of the ease of forming the camming surfaces and other peculiar shapes found therein. Such plastic fabricated hinge assmeblies even with such large number of pieces were relatively inexpensive to fabricate, but the load bearing capacity was limited by the physical characteristics of the plastic material. Metal cam hinges, though having increased load bearing capacity, are considerably more expensive because of the casting or machining required to fabricate the camming surfaces and odd shapes.
More recently hinges utilizing both plastic and metal have been developed. Heretofore, such hinges had hinge sections which were generally comprised of a plastic inner portion, which provides the inner structure of the hinge, and a metal outer portion. The outer metal portion of these hinges includes a metal mounting leaf, and is generally formed from a single flat sheet of metal which is bent and shaped to provide an opened body area, which accepts the plastic portion, and the mounting leaf. The mounting leaf thus consists of two sheets of metal side by side, and has an overall thickness twice that of the sheet forming the body area. The molded plastic portion is fixedly inserted into the opened body portion of the hinge section. The hinge has a light-weight plastic inner structure and a durable outer casing or shell.
The problem with this type of construction, as mentioned above, is that the resulting thickness of the mounting leaf is always twice the thickness of the metal shell. This overlapping metal forming the mounting leaf adds little structural strength to the body of the hinge, but increases the cost of the hinges, especially if high-priced metal such as stainless steel is used. Also, the fabrication costs of such hinges are high because of the considerable bending and shaping which is required to form the metal body of such sections. In addition, the thicker the metal sheet, the more difficult the bending and forming operations.
The present invention contemplates an improvement over the plastic and metal hinge described above, which improved hinge is sturdy, attractive, and economical to fabricate.